The present application is the National Phase of International Application No. PCT/US00/02411, filed Feb. 2, 2000, which was published in English.
1. Field of the Invention
The present invention relates to a process for producing polyphenolic antioxidants with low purine content, from cocoa and other purine-containing plant materials. The invention also relates to an antioxidant composition obtainable using this process. The invention further relates to a nutritional, pharmaceutical or cosmetic antioxidant composition.
2. Related Art
Polyphenolic antioxidants from plant materials derived from cocoa, coffee, tea, and other theobroma species are interesting as they are assumed to be active in preventing cancer, coronary and cardiovascular disease and strokes, and in delaying aging processes. These antioxidants are usually water-soluble and comprise compounds of the chroman type, such as catechin and epicatechin (the stereoisomeric 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxychromans), and oligomerised structures including procyanidin. However, these plant materials also contain purines such as caffeine (1,3,7-trimethyl-2,6-purinedione or 1,3,7-trimethylxanthine) and theobromine (3,7-dimethyl-2,6-purinedione or 3,7-dimethylxanthine), and these components are usually undesired in antioxidant compositions because of their stimulating properties.
Current processes for extracting polyphenols from cocoa comprise treatment of defatted cocoa material with acetone, water/methanol, chloroform and ethyl acetate. Such a process is described in WO 98/09533 (Mars Inc.). A process for removing purines (theobromine and caffeine) from cocoa material by extraction with water of 45-55xc2x0 C. followed by extraction with water of about 100xc2x0 C. is described in U.S. Pat. No. 4,755,391 (Hershey Foods Corp.).
Japanese patent application JP-A-6-9607 concerns the production of tea catechins. The method consists of extracting tea leaves with water, non-selectively adsorbing the purines and catechins on a gel-type adsorbent (e.g., styrene/divinylbenzene) in a column, washing the purines (caffeine) from the column using warm water, and desorbing the catechins from the column using 50-100% aqueous methanol, ethanol or acetone.
Japanese patent application JP-A-10-67771 similarly concerns the production of tea catechins, by non-selectively adsorbing the constituents of a tea extract on a column containing cyclodextrin bound to a crosslinked acrylic resin, and again washing the purines with water and desorbing the catechins with 30-80% aqueous methanol, ethanol or acetone.
Methylxanthines (purines) are usually extracted with chlorinated hydrocarbon solvents, such as chloroform, ethylene dichloride or tetrachloroethane. Methylxanthines are also removed by adsorption on an adsorption material like activated carbon, carob particles or a cation exchange resin as described in U.S. Pat. Nos. 4,956,429, 4,390,698 and 4,444,798.
The problem to be solved with the present invention was to provide a process for producing a natural, fat-free, water-soluble polyphenolic antioxidant composition having a maximum antioxidant activity and a minimum purine content, said process being technically and economically feasible without the use of objectionable chemicals.
The present invention relates to a process for producing polyphenolic antioxidants with low purine content, from cocoa and other purine-containing plant materials, as well as an antioxidant composition obtainable using this process. The invention further relates to a nutritional, pharmaceutical or cosmetic antioxidant composition.
The present invention provides a process for producing a natural, fat-free, water-soluble polyphenolic antioxidant composition having a maximum antioxidant activity and a minimum purine content. This process is technically and economically feasible without the use of objectionable chemicals.